Automated direct immunofluorescence analyses of skin biopsies

Diagnosis of autoantibody- and immune complex-induced skin diseases is primarily based on direct immunofluorescence (DIF) microscopy. DIF staining is usually performed manually and, therefore, is labor intensive. The quality of immunohistochemical results considerably depends on the experience of the person conducting the tests. The novel EUROTide(™) technique in combination with the biochip-based system EUROPath represents a new technology for automation of DIF staining.

Frozen sections of previously characterized skin biopsies from bullous pemphigoid and pemphigus vulgaris patients were incubated with fluorescein-labelled anti-human IgG and complement C3c following the standard manual procedure and, for comparison, applying EUROTide/EUROPath in an automated version.

Both, the manual and the automated procedure, detected IgG and C3c deposits in all samples. However, DIF stainings performed with EUROTide/EUROPath displayed more intense specific IF signals and distinctly less background staining. The detecting antibody could be used at a ×4 higher dilution.

EUROTide/EUROPath applied in an automated system improves diagnostic accuracy and saves reagents. Larger studies in other routine laboratories may further explore the value of the EUROTide/EUROPath technology and may include comparison with other automated stainers.